There are different types of driving mechanisms for electric vehicles and the hub motors are developed to improve the shortcomings of the conventional driving mechanism which require long transmission system and are not suitable for electric wheeled chairs. The conventional hub motors are disclosed in U.S. Pat. Nos. 3,897,843, 4,346,777, 4,913,258, 7,719,412 and 6,974,399, and applicant owned U.S. Pat. No. 6,974,399. All of the disclosures relate to the use of electric motor directly driving the wheels.
Most of the conventional hub motors involve complicated structure so as to have required output work, and the complicated structure includes large number of parts which are costly and take a lot of time for assembly, and maintenance cost is significant.
The conventional hub motors includes coil unit and magnetic unit connected to the rim, and the battery is connected to the frame of the vehicle. In other words, the battery and the hub motor are separately connected to the frame and the wheel. In order to provide power to the hub motor from the battery, the coil unit is fixed to the shaft of the wheel and a hole is drilled from the periphery of the shaft so that the hole extends axially along the shaft. The wires are electrically connected between the coil unit and the battery via the hole. The battery is usually bulky and heavy so that the battery has to be connected to the strong portion of the frame such as the seat tube or the carriage rack. Therefore, the wires have to extend a long distance along the frame and this obviously cannot achieve the aesthetic purpose and requires a significant time to position the wires. In addition, the hole in the shaft may weaken the structure of the shaft.
Some wheels are equipped with power generating members which operate only when the wheels rotate and are not designed for directly providing electric power to the rotation of the wheels. In other words, when the wheels are stationary or the vehicles brake, the kinetic energy is transferred into electric power is stored in the battery attached to the vehicle frame.
The conventional hub motors are complicated and do not have battery directly connected to the rim.
The present invention intends to provide a hub motor to improve the shortcomings of the conventional hub motors.